[Media Services] API doesn't return tags element when none exist

[tombuildsstuff]

👋

We're using the Media Services API version v25.1.0 via the Azure SDK for Go in this package:

"github.com/Azure/azure-sdk-for-go/services/mediaservices/mgmt/2018-07-01/media"

We've noticed when provisioning a Media Services Account that if one or more Tags are provided, they're returned in the response; however if an empty Map is provided then the tags block is omitted from the API response.

For example, for the following API Request:

:authority: management.azure.com
:method: PUT
:path: /subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/190222174436542609/providers/Microsoft.Media/mediaservices/acctestmsafp4ez?api-version=2018-07-01
:scheme: https
content-type: application/json; charset=utf-8
user-agent: Go/go1.11.5 (amd64-darwin) go-autorest/v11.4.0 Azure-SDK-For-Go/v25.1.0 media/2018-07-01 Terraform/0.11.9 terraform-provider-azurerm/dev
authorization: Bearer XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
content-length: 257
accept-encoding: gzip

{
	"location": "westeurope",
	"properties": {
		"storageAccounts": [{
			"id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/190222174436542609/providers/Microsoft.Storage/storageAccounts/acctestsa1fp4ez",
			"type": "Primary"
		}]
	},
	"tags": {
		"Hello": "World"
	}
}

gives the following API response:

{
	"name": "acctestmsafp4ez",
	"id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/190222174436542609/providers/Microsoft.Media/mediaservices/acctestmsafp4ez",
	"type": "Microsoft.Media/mediaservices",
	"location": "West Europe",
	"tags": {
		"Hello": "World"
	},
	"properties": {
		"mediaServiceId": "5d4efe99-acd1-4705-b541-67034cce8c21",
		"storageAccounts": [{
			"id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/190222174436542609/providers/Microsoft.Storage/storageAccounts/acctestsa1fp4ez",
			"type": "Primary"
		}]
	}
}

---

However when no tags are provided in the Request:

:authority: management.azure.com
:method: PUT
:path: /subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/190222174721721594/providers/Microsoft.Media/mediaservices/acctestmsarfshu?api-version=2018-07-01
:scheme: https
content-type: application/json; charset=utf-8
user-agent: Go/go1.11.5 (amd64-darwin) go-autorest/v11.4.0 Azure-SDK-For-Go/v25.1.0 media/2018-07-01 Terraform/0.11.9 terraform-provider-azurerm/dev
authorization: Bearer XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
content-length: 242
accept-encoding: gzip

{
	"location": "westeurope",
	"properties": {
		"storageAccounts": [{
			"id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/190222174721721594/providers/Microsoft.Storage/storageAccounts/acctestsa1rfshu",
			"type": "Primary"
		}]
	},
	"tags": {}
}

The tags block is omitted from the API response:

{
	"name": "acctestmsarfshu",
	"id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/190222174721721594/providers/Microsoft.Media/mediaservices/acctestmsarfshu",
	"type": "Microsoft.Media/mediaservices",
	"location": "West Europe",
	"tags": {

	},
	"properties": {
		"mediaServiceId": "cb3cc364-9571-4f1a-b05c-31429ac41d60",
		"storageAccounts": [{
			"id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/190222174721721594/providers/Microsoft.Storage/storageAccounts/acctestsa1rfshu",
			"type": "Primary"
		}]
	}
}

---

Would it be possible to fix this API to return an empty Tags block when no tags are set?

FYI I've also raised a bug in the Azure SDK for Go where the mediaServiceId value isn't parsed out correctly - however this looks to be a Service issue rather than an SDK issue.

Thanks!

[salameer]

Hi @quintinb can you kindly look into this reported issue?

[akucer]

Azure Media Services will omit properties that are not required if they have the default value. As Tags are not a required property, when an empty Tag block is set it is omitted in the API response. We do not plan on changing this behavior.

[akucer]

Closing

[tombuildsstuff]

@akucer this is different to the behaviour of every other Azure API, which returns the value of fields in all cases (such as in this one when there's no elements) - which I believe is part of the ARM Specification - so I'd suggest this might be worth re-considering?

[tombuildsstuff]

ping @akucer